Robertson, 27, took to Instagram to announce her engagement, reported People magazine.
"After long time of patiently searching, I found the ultimate gem," she wrote on Instagram, sharing a picture of the ring.
"Our story starts here... I said yes to my best friend for life," she captioned the second photo of her and Loflin on beach.
Rebecca isn't the only one in the dynasty, who will be tying the knot in the near future. Reed Robertson will also get hitched to his longtime girlfriend, Brighton Thompson.